Case ReportSpinal Accessory Nerve Duplication: A Case Report andLiterature Review

EleniPapagianni ,1,2PanagiotaKosmidou ,3SotiriaFergadaki,1AthanasiosPallantzas,4

Panagiotis Skandalakis,2 and Dimitrios Filippou 2

1Department of Otolaryngology-Head and Neck Surgery, 417 Army Share Fund Hospital, Athens, Greece2Department of Anatomy and Surgical Anatomy, Medical School, National and Kapodistrian University of Athens,Athens, Greece3Department of Otolaryngology-Head and Neck Surgery, Evaggelismos General Hospital, Athens, Greece4Plastic and Reconstructive Surgery Department, Evaggelismos General Hospital, Athens, Greece

Correspondence should be addressed to Eleni Papagianni; eleni.papagianni@yahoo.com

Received 29 January 2018; Accepted 15 March 2018; Published 1 April 2018

Academic Editor: I. Todt

Copyright © 2018 Eleni Papagianni et al. (is is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work isproperly cited.

Aim of the present study is to expand our knowledge of the anatomy of the 11th cranial nerve and discuss the clinical importanceand literature pertaining to accessory nerve duplication. We present one case of duplicated spinal accessory nerve in a patientundergoing neck dissection for oral cavity cancer. (e literature review confirms the extremely rare diagnosis of a duplicatedaccessory nerve. Its clinical implication is of great importance. From this finding, a further extension to our knowledge of theexisting anatomy is proposed.

1. Introduction

Cervical lymphadenectomy or neck dissection is a com-monly performed procedure concerning the management ofhead and neck cancer. A major complication associated withthis surgery constitutes the injury to the spinal accessorynerve in addition to injury to the great vessels and lymphaticvessels [1]. Successful surgical management of these patientsconsequently depends on recognizing the anatomic struc-tures that may potentially put a positive outcome at risk.

(e spinal accessory nerve (SAN) is unique in that itshares its innervation from both the medulla and the spinalcord. (e cranial fibers, which originate from the nucleusambiguus in the medulla, are designated to innervate thelaryngeal muscles. (e spinal component is composed offibers from the anterior horn cells of the upper five or sixcervical vertebrae. (ese spinal fibers enter the posteriorcranial fossa via the foramen magnum, merge with thecranial fibers, and then exit through the jugular foramenalong with the fibers of the glossopharyngeal and vagus

nerves. (e SAN branches off passing deep into the pos-terior belly of the digastric muscle to supply the sterno-cleidomastoid. Finally, it transverses the posterior triangleof the neck, superficial to the prevertebral fascia, andterminates with its branches in the deep surface of thetrapezius muscle. Some studies have also documentedinnervation of the upper trapezius directly from the cervicalplexus [2].

Spinal accessory nerve can be a cause of scapular wingingand shoulder dysfunction. Despite the use of nerve-sparingsurgery, the frequency of shoulder morbidity after modifiedradical or selective neck dissection remains high. A highincidence of shoulder morbidity may be because of theunrecognized anatomical patterns and branching of CN XI.(e most common etiology by far is iatrogenic damage(75%) secondary to surgical procedures involving the pos-terior triangle of the neck. (ese are often recognizedperioperatively. Understanding anatomical variations of thespinal accessory nerve is therefore of crucial importance toavoid iatrogenic injury [2, 3].

HindawiCase Reports in OtolaryngologyVolume 2018, Article ID 1027831, 3 pageshttps://doi.org/10.1155/2018/1027831

We report a single case of duplicated SAN on the left sidein a patient undergoing neck dissection and discuss theclinical implications, management, and literature pertainingto SAN duplication.

2. Case Report

A 62-year-old Caucasianmale presented at the Otolaryngology-Head and Neck Surgery Department of the 417 Army ShareFund Hospital of Athens with an abnormal lesion of the oralcavity on the left side. (e lesion was observed one year agoafter a dental surgery was performed. It appeared as a painful,nonhealing ulcer, which displayed gradual growth. Regardinghis medical history, he suffered from arterial hypertension,managed with angiotensin II receptor blocker. He had noknown allergies and used to be a heavy smoker ten years ago(30 pack-years) and a social drinker. Biopsy of the lesionshowed squamous cell carcinoma of the internal surface of the

posterior third of the body of themandible, clinically staged asT3N2bM0 after cranial and cervical MRI (Figures 1 and 2)and thoracic CT. At the time of his appearance at our de-partment, the patient had undergone three courses of che-motherapy for a less invasive surgery to be performed. Afterchemotherapy, his work up included a reassessment withPET/CT and cranial and cervical MRI, which showed a sig-nificant reduction of the initial mass in the primary site andthe cervical lymphnodes.

Following this, the patient underwent resection ofthe primary mass on the mandible and modified radicalneck dissection of the levels II to V preserving CN XI. In-traoperatively, a duplication of the spinal accessory nervewas observed, 2 cm inferiorly to the mandible (Figure 3). (efirst branch was identified penetrating the sternocleido-mastoid muscle and the secondary branch fusing withthe cervical plexus. (e patient recovered from the pro-cedure with minimal regional pain and no evidence of SANdysfunction.

3. Discussion

Spinal accessory nerve duplication is an extremely rarephenomenon. To our knowledge, there have been no re-ported cases of spinal CN XI duplication. However, oneanatomical study on fifty-six cadavers (112 sides) hasdocumented two cases (1.8%) where the nerve was foundduplicated, one intracranially and one extracranially [4].Knowledge of the variants of accessory nerve anatomymaybe critical to avoid iatrogenic surgery since SAN is thesecond most commonly affected peripheral nerve (18%)during surgery in a study, following the median nerve(21.3%) [5].

SAN injury results in loss of motor function of thetrapezius muscle and primarily leads to shoulder dysfunc-tion and shoulder pain. (e shoulder syndrome after neckdissection was first described by Erwing and Martin in 1952,

Figure 1: Imaging of the lesion in the internal surface of themandible on the left in cranial MRI T1 with gadolinium (blackarrow).

Figure 2: Imaging of the lesion in the internal surface of themandible on the left in cranial MRI T2 (white arrow).

Figure 3: Image captured from left modified radical neck dis-section, showing a duplicated spinal accessory nerve. (a) Firstbranch of CNXI. (b) Second branch of CNXI. (c) SCMmuscle. and(d) Mandible.

2 Case Reports in Otolaryngology

and it includes constant shoulder pain, shoulder tilt anddrop, winged scapula, difficulty of shoulder retraction, re-striction in anterior flexion movement and active abductionmovements at shoulder joint, and abnormal electromyog-raphy findings [6].

(e type of neck dissection has major impact on theshoulder dysfunction. Modified radical neck dissection(MRND) increases shoulder morbidity when compared toSelective neck dissection. (e frequency of postoperativemorbidity of SAN was 46.7% for radical neck dissection,42.5% for selective neck dissection, and 25% for modifiedneck dissection in a study. Modified neck dissection hassimilar regional control rates to more comprehensive op-erations in appropriately selected patients and significantlyreduces the risk of functional disability [7]. Additionally,technique of neck dissection has significant impact onshoulder dysfunction in postoperative period. Contempo-rary findings regarding the anatomical patterns of CN XIand cervical nerve innervation of the trapezius muscle couldhave implications for the development of a modified radicalneck dissection (MRND) technique [3, 6].

As the exact role of cervical nerve innervation of thetrapeziusmuscle is still unclear, the nerves should be preservedwhenever possible [3]. (e safest identification of SAN is inthe posterior neck triangle where it may be recognized exitingfrom the posterior border of the sternocleidomastoid muscleat Erb’s point [7]. Should the SAN be seriously damaged(transected or a nonrecovering neuroma-in-continuity isobserved), treatment would include a primary end-to-end orgraft repair. Furthermore, nerve transfers, such as the lateralpectoral nerve, may be considered in cases of proximal injuryor delayed presentation [8].

4. Conclusion

(e identification of anatomical variations of CN XIbranching in the neck provides invaluable information tosurgeons seeking to preserve the motor branches of thenerve during neck dissection.

Consent

Written consent for publication of the patient’s details wasobtained.

Conflicts of Interest

(e authors declare that they have no conflicts of interest.

References

[1] K. J. Contrera, N. Aygun, B. K. Ward, Z. Gooi, andJ. D. Richmon, “Internal jugular vein duplication and fenes-tration: case series and literature review,” Laryngoscope,vol. 126, no. 7, pp. 1585–1588, 2016.

[2] S. Macaluso, D. C. Ross, T. J. Doherty, C. D. Doherty, andT. A. Miller, “Spinal accessory nerve injury: a potentiallymissed cause of a painful, droopy shoulder,” Journal of Backand Musculoskeletal Rehabilitation, vol. 29, no. 4, pp. 899–904,2016.

[3] B. Lanisnik, “Different branching patterns of the spinal accessorynerve: impact on neck dissection technique and postoperativeshoulder function,” Current Opinion in Otolaryngology & Headand Neck Surgery, vol. 25, no. 2, pp. 113–118, 2017.

[4] R. S. Tubbs, O. O. Ajayi, F. N. Fries, R. J. Spinner, andR. J. Oskouian, “Variations of the accessory nerve: anatomicalstudy including previously undocumented findings-expandingour misunderstanding of this nerve,” British Journal of Neu-rosurgery, vol. 31, no. 1, pp. 113–115, 2017.

[5] L. Rasulic, A. Savic, F. Vitosevic et al., “Iatrogenic peripheralnerve injuries—Surgical treatment and outcome: 10 years’experience,” World Neurosurgery, vol. 103, pp. 841e6–851e6,2017.

[6] A. Mathialagan, R. K. Verma, andN. K. Panda, “Comparison ofspinal accessory dysfunction following neck dissection withharmonic scalpel and electrocautery—A randomized study,”Oral Oncology, vol. 61, pp. 142–145, 2016.

[7] V. Popovski, A. Benedetti, D. Popovic-Monevska, A. Grcev,A. Stamatoski, and J. Zhivadinovik, “Head and neck spinalaccessory nerve preservation in modified neck dissections:surgical and functional outcomes outcomes,” Acta Oto-rhinolaryngologica Italica, vol. 37, no. 5, pp. 368–374, 2017.

[8] A. A. Maldonado and R. J. Spinner, “Lateral pectoral nervetransfer for spinal accessory nerve injury,” Journal of Neuro-surgery: Spine, vol. 26, no. 1, pp. 112–115, 2017.

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